This invention relates in general to the field of battery packaging. Solid-state batteries are advantageous, since they possess a number of very desirable characteristics, including the absence of liquid leakage or gassing, long shelf life, and operation over a wide temperature range. A number of solid-state batteries have been proposed.
One such battery which has received wide attention is one employing a polymer cathode, a polymer electrolyte, and a lithium anode. For an example of a lithium anode battery, see U.S. Pat. No. 4,997,732 issued to Austin et al. ("Austin et al.").
Lithium is highly reactive, so the lithium battery cell must be sealed in a protective material to exclude air, water and other gases from contacting the lithium. The prior art battery cell of Austin et al. shown in FIG. 1 comprises a battery assembly 102, including a thin laminar battery cell 104 shown in phantom, enclosed by a multi-layered protective sheet material 106. Connected to the battery cell 104 are terminals 108 and 110. The multi-layered protective sheet material 106 is made of an inner thermoplastic layer, a middle metal foil layer and an outer thermoplastic layer.
A problem with the prior art battery assembly is that a defective lithium battery cell may form gases that could threaten to burst the seal or the protective sheet material 106 and expose the reactive lithium to the external environment. It is therefore desirable to provide an improved battery assembly in which this problem is not present.